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Thread: LTG swap into 2009 Acadia LLT?

  1. #1
    Tuner in Training V8 Supra Builder's Avatar
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    LTG swap into 2009 Acadia LLT?

    EDIT: I ended up selling the vehicle, but I'll leave all of this up for future use.

    So my wife's Acadia's LLT gave up the ghost after 200K miles. I've never liked working on this layout, and have been reading about the I4 LTG to replace the V6 LLT. Used LLT engines command way more than they are worth, and rebuilding one is just putting good money after bad IMO. The LTG makes about the same amount of HP & Torque. I don't have any experience with the smaller motors. Is this a feasible swap from a VCM perspective?

    As far as fitment goes, it looks like Chevy used the LTG engine through 2019 in the similar Traverse, albeit hooked to a 9 speed transaxle. I'd just as soon keep the OEM 6T75.

    Thanks for any advice.
    Last edited by V8 Supra Builder; 04-18-2020 at 12:49 PM.
    My prior projects include Chevy Gen 1 V8 into an FB RX-7, Gen 3 V8s into an FC RX-7, a MK3 Supra, a BMW E34, and an LT1 into a 280Z. Still have the Datsun, a 383 LT4 Trans Am, and some bikes.

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    Tuning Addict 5FDP's Avatar
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    I see no way of controlling that engine. The acadia of that era was only powered by a 3.6 and none of the other GM suv's (traverse/outlook/enclave) ever ran a turbo 4 cylinder in that generation either.

    Like you said the 2018+ Traverse started running it and that is a totally different computer. Finding another LLT engine or rebuilding yours is the only way to get that vehicle back on the road again.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
    Tuner in Training V8 Supra Builder's Avatar
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    Thanks for the reply. I need to look at pinouts for both vehicles and see if there are any definitive roadblocks. Worst case, it seems like using the Traverse (or similar) engine and transmission along with the matching VCM may be a possibility. I need to see if the vehicle is supported in HPT as well. Another possibility may be dual VCMs, I'm using that scenario on a Gen 3 swap into my Durango- GM VCM for the engine & 4L80, Mopar VCM for body functions.

    I think I'd rip everything out and go with a standalone Painless harness before I'd put another LLT in there.
    My prior projects include Chevy Gen 1 V8 into an FB RX-7, Gen 3 V8s into an FC RX-7, a MK3 Supra, a BMW E34, and an LT1 into a 280Z. Still have the Datsun, a 383 LT4 Trans Am, and some bikes.

  4. #4
    Tuning Addict 5FDP's Avatar
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    Things get really complicated when everything is ran over CAN-BUS. No doubt you are going to lose all ABS and stability control if you used two computers. None of the CAN stuff will sync up.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  5. #5
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    I ended up selling the vehicle, but I'll leave all of this up for future use.

    After doing some more reading, it looks a lot more feasible to use the engine & trans (sort of) from a 2013-14 Maibu/Regal since they use a 6T70 that is similar to the Acadia's 6T75. Since the Acadia is a heavier vehicle, a 6T75 would be better, but the bellhousings are different, I have not found an LTG vehicle that uses the 6T75. I found the 2013 Caddy SRX used the 6T70 but with a lower final drive (3.39)- lower than the 3.16 of the Acadia. The Malibu/Regal is 2.77, a no-go for the application. Looking at pics of the transmissions, it looks like you could make one out of two- use the front case from the Malibu and the rear section from the SRX. I've done this with transfer cases so it would be nice if this worked out the same. What's really cool are th erpices of the motors & trans- like $800 and $400 for 30K mile units. The LLT goes for $1,300 as a core, and the 6T75 with over 100K miles is still around $1K. Looks like those have had plenty of internal wave plate issues, so it would still need to be rebuilt.

    Electronics would no doubt be a huge roadblock. Looking at the VCM (I have one from a late model Malibu and a spare from the Acadia), there are a lot more pins on the Malibu. Counting pins, the later model computer has three same-size connectors with 216 small pins plus 1 large pin per connector for 219 total. The Acadia has two different size connectors with 148 small pins plus 6 large ones. I'd need wiring diagrams from both to see what all is involved. Fortunately the downloadable factory manuals are like $10. If I decide to pursue this, that would be my first step.

    EDIT- Also both the Acadia and Malibu/Regal are supported in HPT. The newer Traverse is not.
    Last edited by V8 Supra Builder; 04-18-2020 at 12:49 PM. Reason: Added info
    My prior projects include Chevy Gen 1 V8 into an FB RX-7, Gen 3 V8s into an FC RX-7, a MK3 Supra, a BMW E34, and an LT1 into a 280Z. Still have the Datsun, a 383 LT4 Trans Am, and some bikes.

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    I had a similar idea. The LFX is one of the siblings to the LLT that has some upgrades improving reliability, power, AND it was MUCH cheaper. I did not have my own shop at the time but I contacted the guys at Tracey Lewis Performance for some help. They were able to procure an LFX from a 2014 Impala and swap it in to my 2010 Traverse. They did a good job, it looks like everything is pretty straight forward. They fabbed some exhaust manifolds, coded out the bank 1/2 cats, and some other odds/ends. It turned out great! I get 2MPG better mileage and it has better power. I am going through the transmission tune a bit to round out some better highway manners in the stock 6T75 but over all I am very happy and have more mods planned.

    Long story short, I would recommend swapping in an LFX